Generally, adding all strength will give you more damage than adding all dexterity.
Ultimately you're build has to be built around a purpose. If you plan to cata, all strength would be your best bet.
On the other hand, if you plan to solo in the arena, you should get your dex to 80-100 with items and the rest into str to protect against monster critical strikes.
Barbarian GuideIf you need any more help, feel free to shoot me a pm
This post was edited by xxtmanxx on Feb 4 2010 01:34pm